The present technique relates generally to the measurement of the overall motion undergone by an object. More specifically, the present technique relates to identifying a period of interest in the motion of an object within a complex system using multiple sources.
Both living and mechanical complex systems may be formed from the combination of an assortment of components. In the case of living systems, the components may be the various organs and tissues that comprise the body of an organism. In the case of a mechanical system, the components may be the various parts forming the working mechanism of the system. In these types of complex systems a variety of the components may be located on the interior of the system, such as within the organism or mechanism body, where they are not subject to easy observation or examination.
Furthermore, the interior components may move relative to one another and to the exterior of the system. For example, in the context of a living organism, organs, such as the heart, lungs, diaphragm, stomach, and so forth, may move independent of one another (such as the heart and stomach) or in conjunction with one another (such as the lungs and diaphragm). Similarly, mechanical complex system may have interior moving parts, such as rotors, turbines, levers, arms, pistons, valves, and so forth, which, depending on the mechanism of operation, may move independent of or in conjunction with one another.
The difficulty in observing the interior components of such moving systems may make it difficult to observe the synchrony, or lack thereof, of the moving components. Furthermore, as one might expect, the motion of one interior component may contribute to the overall motion of connected or proximate interior components. The overall motion of a component may be difficult to ascertain without knowing the motion of all possible contributors to the overall motion. For example, in the context of the living organism, the motion of the heart may be of interest for various reasons, including diagnostic imaging or interventional procedures. The overall motion of the heart, however, may not be simply attributable to cardiac contractions but may also be attributable to respiration, i.e., lung and diaphragm motion, to skeletal muscular contractions, or to other proximate muscular motions. Similarly, within a mechanical system, the overall motion of a component, such as a turbine, may be attributable not only to the motion of the component itself but may also be attributable to other proximate moving components which are operating independent of or in conjunction with the component of interest.
In some cases, the overall motion of a component may be of interest, not simply the motion attributable to the component. For example, in a mechanical system, the overall motion of an internal component may indicate a problem, such as a component moving outside of the tolerance range, or a pending problem or failure, such as a vibration or stressful motion indicating the pending breakage or failure of a component. Similarly, in a living organism, the overall motion of an organ, such as the heart or lungs, may be of interest for imaging or interventional purposes, such as to perform motion correction or artifact correction.
Determining the overall motion of a component may be difficult, however. In particular, sensors or component specific information sources may only provide information about one aspect of the overall motion of a component. For example, in the case of a turbine, internal sensors may only report a measure, such as RPM, which provides information about the rotation of the turbine, but no information about proximate moving components that may be moving the turbine incidental to their own motion.
Similarly, in the context of a living organism, it may be desirable to know the overall motion of the heart. Techniques such as electrocardiography (ECG), however, only provide information regarding the cardiac phase of the heart, i.e., what state of contraction the heart is in at a point in time. Information such as the motion of the respiratory organs, i.e., the lungs and/or diaphragm, which may contribute to the overall motion of the heart, is not captured by a technique, such as ECG, which simply ascertains information about the contractions of the heart. It may, therefore, be desirable to characterize the overall motion undergone by an internal component of a complex system for analysis of the system.